Abstract
Palladium supported on ceria is an effective catalytic material for three-way automotive catalysis, catalytic combustion, and solid-oxide fuel cell (SOFC) anodes. The morphology, oxidation state, and particle size of Pd on ceria affect catalytic activity and are a function of experimental conditions. This work utilizes ab initio thermodynamics using density functional theory (DFT) (DFT+U) methods to evaluate the stability of Pd atoms, PdOx species, and small Pd particles in varying configurations on CeO2 (111), (110), and (100) single crystal surfaces. Over specific oxygen partial pressure and temperature ranges, palladium incorporation to form a mixed surface oxide is thermodynamically favorable versus other single Pd atom states on each ceria surface. For example, Pd atoms may incorporate into Ce fluorite lattice positions in a Pd4+ oxidation state on the CeO2 (111) surface. The ceria support shifts the transition between formal Pd oxidation states (Pd 0, Pd2+, Pd4+) relative to bulk palladium and stabilizes certain oxidized palladium species on each surface. We show that temperature, oxygen pressure, and cell potential in a SOFC can influence the stable states of palladium supported on ceria surfaces, providing insight into structural stability during catalytic operation.
| Original language | English (US) |
|---|---|
| Article number | 084701 |
| Journal | Journal of Chemical Physics |
| Volume | 131 |
| Issue number | 8 |
| DOIs | |
| State | Published - Sep 7 2009 |
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All Science Journal Classification (ASJC) codes
- Physics and Astronomy(all)
- Physical and Theoretical Chemistry
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Ab initio thermodynamic evaluation of Pd atom interaction with CeO 2 surfaces. / Mayernick, Adam D.; Janik, Michael John.
In: Journal of Chemical Physics, Vol. 131, No. 8, 084701, 07.09.2009.Research output: Contribution to journal › Article
TY - JOUR
T1 - Ab initio thermodynamic evaluation of Pd atom interaction with CeO 2 surfaces
AU - Mayernick, Adam D.
AU - Janik, Michael John
PY - 2009/9/7
Y1 - 2009/9/7
N2 - Palladium supported on ceria is an effective catalytic material for three-way automotive catalysis, catalytic combustion, and solid-oxide fuel cell (SOFC) anodes. The morphology, oxidation state, and particle size of Pd on ceria affect catalytic activity and are a function of experimental conditions. This work utilizes ab initio thermodynamics using density functional theory (DFT) (DFT+U) methods to evaluate the stability of Pd atoms, PdOx species, and small Pd particles in varying configurations on CeO2 (111), (110), and (100) single crystal surfaces. Over specific oxygen partial pressure and temperature ranges, palladium incorporation to form a mixed surface oxide is thermodynamically favorable versus other single Pd atom states on each ceria surface. For example, Pd atoms may incorporate into Ce fluorite lattice positions in a Pd4+ oxidation state on the CeO2 (111) surface. The ceria support shifts the transition between formal Pd oxidation states (Pd 0, Pd2+, Pd4+) relative to bulk palladium and stabilizes certain oxidized palladium species on each surface. We show that temperature, oxygen pressure, and cell potential in a SOFC can influence the stable states of palladium supported on ceria surfaces, providing insight into structural stability during catalytic operation.
AB - Palladium supported on ceria is an effective catalytic material for three-way automotive catalysis, catalytic combustion, and solid-oxide fuel cell (SOFC) anodes. The morphology, oxidation state, and particle size of Pd on ceria affect catalytic activity and are a function of experimental conditions. This work utilizes ab initio thermodynamics using density functional theory (DFT) (DFT+U) methods to evaluate the stability of Pd atoms, PdOx species, and small Pd particles in varying configurations on CeO2 (111), (110), and (100) single crystal surfaces. Over specific oxygen partial pressure and temperature ranges, palladium incorporation to form a mixed surface oxide is thermodynamically favorable versus other single Pd atom states on each ceria surface. For example, Pd atoms may incorporate into Ce fluorite lattice positions in a Pd4+ oxidation state on the CeO2 (111) surface. The ceria support shifts the transition between formal Pd oxidation states (Pd 0, Pd2+, Pd4+) relative to bulk palladium and stabilizes certain oxidized palladium species on each surface. We show that temperature, oxygen pressure, and cell potential in a SOFC can influence the stable states of palladium supported on ceria surfaces, providing insight into structural stability during catalytic operation.
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U2 - 10.1063/1.3207283
DO - 10.1063/1.3207283
M3 - Article
VL - 131
JO - Journal of Chemical Physics
JF - Journal of Chemical Physics
SN - 0021-9606
IS - 8
M1 - 084701
ER -